SB2026070251 - Use-after-free in Linux kernel netfilter

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Main Vulnerability Database SB2026070251

SB2026070251 - Use-after-free in Linux kernel netfilter

Published: July 2, 2026

Security Bulletin ID SB2026070251
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Use-after-free (CVE-ID: CVE-2026-53349)

CWE-ID: CWE-416 - Use After Free

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a local privileged user to cause a denial of service.

The vulnerability exists due to a use-after-free in netfilter nf_conntrack expectation handling when processing an expected connection after a NAT helper module has been unloaded. A local privileged user can unload a NAT helper module while live expectations remain and then trigger the expected connection to cause a denial of service.

Reaching the vulnerable state requires CAP_SYS_MODULE in the initial user namespace to remove a NAT helper that still has live expectations.


Remediation

Install update from vendor's website.

References